1. Field
An exemplary embodiment of the present invention relates to an e-fuse array circuit.
2. Description of the Related Art
A common fuse may be programmed in a wafer state because the data of the fuse is determined based on whether the fuse is cut by a laser or not. However, it is difficult to program the fuse after the wafer is mounted on a package. An e-fuse is used to overcome the disadvantage. The e-fuse stores data by changing resistance between a gate and a source by using a transistor.
FIG. 1 is a diagram illustrating an e-fuse including a transistor. The e-fuse may operate as a resistor or a capacitor.
Referring to FIG. 1, the e-fuse includes a transistor T. A power source voltage is supplied to the gate G of the transistor T, and a ground voltage is supplied to the drain/source D/S thereof.
If a common power source voltage that the transistor may tolerate is supplied to the gate, the e-fuse operates as a capacitor C. Accordingly, there is no electric current that flows between the gate G and the drain/source D/S. If a high power source voltage that the transistor T may not tolerate is supplied to the gate G, the gate oxide of the transistor T is ruptured, and the gate G and the drain/source D/S are shorted, so that the e-fuse operates as a resistor. Accordingly, an electric current flows between the gate G and the drain/source D/S. The data of the e-fuse is determined based on a resistance value between the gate G and the drain/source D/S of the e-fuse using this phenomenon. Here, the data of the e-fuse may be immediately determined without an additional sensing operation by (1) increasing the size of the transistor T or (2) reducing the size of the transistor T and sensing an electric current flowing through the transistor T using an amplifier. The two methods may not be effectively used, because the size of the transistor T that forms the e-fuse must be increased, or the amplifier for amplifying data must be included in each e-fuse.